1. Field of the Invention
The present invention relates generally to broadband telecommunications, and particularly to a system and method for provisioning broadband service in a Point-to-Point over Ethernet (PPPoE) network using Dual-Tone MultiFrequency (DTMF) tones.
2. Description of Related Art
While high-speed or Broadband Internet connections to large businesses have been in existence for some time, Broadband Internet connections to homes and small businesses have only recently become more commonplace. Broadband technologies such as ISDN (Integrated Services Digital Network), cable modems, satellite, and DSL (Digital Subscriber Line), are all competing for market share. The two technologies at the forefront, DSL and cable, offer much faster Internet access than dial-up modems, for a cost substantially lower than ISDN.
Analog modems over regular telephone lines are not fast enough for today's Broadband multi-media content. In fact, so-called 56 Kbps modems actually move data at approximately 44 Kbps because of telephone-line imperfections. Furthermore, these modems only reach that speed when receiving data, not sending it.
Typically, analog modems generally connect to the Internet by dialing-up an Internet Service Provider (ISP) over a regular telephone line. This connection is a permanent connection known as a physical circuit. Generally, a Point-to-Point (PPP) data link protocol is used to provision the physical circuit.
Basic ISDN transfers data at 56 Kbps, while an improved form of ISDN has a maximum speed of 128 Kbps. ISDN is, however, expensive, running up to several hundreds of dollars a month. Furthermore, ISDN is only approximately four times the speed of a 33.6 Kbps modem.
Another option, satellite, which uses the same type of mini-dish antenna typical of broadcast television can receive data at up to 400 Kbps. However, transmitted data typically still has to be sent through a traditional analog modem at 33.6 Kbps or 56 Kbps.
Cable modems, enable one to hook up a computer to a local cable television line and receive data at about 1.5 Mbps. This data rate far exceeds that of both 56 Kbps analog modems, and the 128 Kbps of ISDN. The actual bandwidth for Internet service over a cable TV line is up to 27 Mbps for receiving data, and up to about 2.5 Mbps of bandwidth for transmitting data. However, since the local provider may not be connected to the Internet on a line faster than a T1 at 1.5 Mbps, a more likely data rate will be closer to 1.5 Mbps. Cable, however, suffers the drawback that it is carried on existing cable television lines, which not all premises are equipped with. Furthermore, available bandwidth is shared with other cable users in the same geographic area.
DSL, on the other hand, is 20 times faster than satellite connections, 60 times faster than ISDN, and 250 times faster than 33.6 Kbps analog modems. DSL or xDSL, as used herein, refers to different variations of DSL, such as ADSL (Asymmetric Digital Subscriber Line), HDSL(High bit-rate Digital Subscriber Line), and RADSL (Rate Adaptive Digital Subscriber Line). Assuming that the location of one's home or business is close enough to a telephone company central office (CO) that offers DSL service, one can receive data at rates up to 6.1 megabits (millions of bits) per second. More typically, individual connections will provide from 1.544 Mbps to 512 Kbps downstream and about 128 Kbps upstream. Best of all, those bits are transmitted via the same copper wire, otherwise known as a twisted pair, used for telephone calls but without the complex setup of ISDN. DSL does this by taking advantage of unused frequencies that exist on standard telephone lines. An added advantage is that the original POTS (Plain Old Telephone Service) frequencies remain free to handle voice traffic over the same twisted pair. Yet another advantage is that unlike cable modems, DSL users do not share their Broadband connections with others in the same geographical area.
However, not all twisted pairs can support DSL service. The quality of different twisted pairs vary according to geographic region, age, gauge, and the distance from the CO. Speed of transmission slows with an increase in distance between the customer premises and the CO.
Furthermore, bridged taps and splices, which are unconnected copper cable between the customer premises and the CO (the result of anticipating customer needs for future expansion or the result of reassigning copper once routed to one customer to be used by another customer) may also prevent the transmission of DSL signals.
In addition, load coils will prevent the transmission of high-frequency DSL signals within a loop. Load coils were deployed to improve the voice quality of loops greater than 18,000 feet. Still further, Digital Loop Carriers (DLCs) were designed in the early 1970s to combine multiple voice channels (as many as 24 voice lines) into a single T1 transport line. They provided an economical and quick way of adding additional voice lines for remote customers. DLCs use digital techniques similar to those used by DSL equipment. Since the bandwidth of the copper pair is already in use by the DLC equipment, DSL will perform at a greatly reduced rate, if at all, depending on the volume of voice calls and the type of DLC equipment. Connecting DSL equipment to DLCs can also adversely affect the performance of the voice-based system.
Moreover, line noise from adjacent copper cable can affect the performance of DSL service. A number of contributing factors, including cable shielding, unbalanced lines, and the presence of adjacent T1 circuits, can cause line noise. In turn, line noise can affect the error rates of data transmission, resulting in decreased transmission speeds for DSL equipment.
All of these factors affect the ability of the existing infrastructure to carry DSL signals. Depending on local conditions, some of these impediments may make DSL service impossible. Therefore, the fact that voice communication over an existing twisted pair works occurs, is no indication that DSL service can be provisioned over the same twisted pair.
Typically, a request for DSL service is initiated from the user to the DSL ISP. The DSL ISP then requests the local telephone provider to provision a line from the local telephone provider to the user. If the local telephone provider ascertains that DSL service can be provisioned over the user's existing twisted pair, he/she connects a twisted pair to the customer premises and to the CO. The CO is then connected to the DSL network through a router.
Once the twisted pair has been provisioned for DSL service, a technician is then sent out to set up and install a DSL modem at the user premises. It has, however, been estimated, that a typical service call to set up a DSL modem, currently costs in the region of $300 for the DSL ISP.
Recent developments have all but eliminated the need for sending a technician to the user premises to set up and install the DSL modem. Now, the user merely connects the DSL modem to the provisioned twisted pair and a power source, and turns the modem on. The modem then establishes a DSL circuit with the DSL ISP and automatically configures itself with important network information from the ISP, such as an Internet Protocol (IP) address. Further details of such automatic configuration can be found in U.S. patent application Ser. No. 09/668,623, which is incorporated herein by reference.
Today, most DSL communications traverse public networks, such as frame relay networks, over Permanent Virtual Circuits (PVCs). As the name implies, PVCs are static bidirectional connections that are established ahead of time between two end stations. The PVC is permanently available to the user as if the connection is a dedicated or leased line that is continuously reserved for that user. The PVC connection is established manually when the network is configured and consists of the end stations, the transmission medium, and all of the switches between the end stations. After a PVC has been established, a certain amount of bandwidth is reserved for the PVC, and the two end stations do not need to set up or clear connections. Further details about PVC can be found in Request for Comments (RFC) 2955 and RFC 3070 both of which are hereby incorporated by reference.
More recently, the Incumbent Local Exchange Carriers (ILECs), which are traditional local telephone companies such as one of the Regional Bell companies (RBOCs), for example PACIFIC BELL, have started using Point-to-Point over Ethernet (PPPoE) to run the PPP protocol over Ethernet for DSL connections. One such ILEC is AMERITECH of Chicago, U.S.A. PPPoE supports the protocol layers and authentication widely used in PPP and enables a point-to-point connection to be established in the normally-multipoint architecture of Ethernet.
PPPoE allows ILECs to sublease their lines to other ISPs, while making it easier for ISPs to provision services to support multiple users across a dedicated DSL connection. Still further, PPPoE also simplifies the end-user experience by allowing a user to dynamically select between ISPs. However, PPPoE complicates the process of delivering PPP over DSL because for each login a user must supply a username, password, and domain. PPPoE also requires the users to install additional PPPoE client software on their client computers.
The PPPoE functionality, available now in version 2.1 of the REDBACK Subscriber Management System (SMS) 1000 system software, is based on a proposed Internet Engineering Task Force (IETF) specification developed jointly by REDBACK NETWORKS, client software developer ROUTERWARE (Newport Beach, Calif.) and WORLDCOM subsidiary UUNET Technologies (Fairfax, Va.). Further details on PPPoE can be found in RFC 2516 which is hereby incorporated by reference.
The typical user experience with a DSL service using PPPoE involves the following steps:                (1) The user deploys a carrier-supplied Bridging DSL modem pre-configured with a PVC;        (2) The user connects the Ethernet port on a Network Interface Card (NIC) in a client computer to the Ethernet interface on the DSL modem;        (3) The user installs the PPPoE driver;        (4) Using standard WINDOWS dial-up networking capabilities, the user sets up a new PPP connection over the Ethernet-connected DSL modem; and        (5) The user clicks on the particular dial-up networking connection, provides the appropriate user name, domain, and password and clicks connect.        
The result is the establishment of a PPP session over Ethernet. This PPP session over Ethernet is bridged by the DSL modem to an ATM PVC which connects in an ISP POP (Point of Presence) to a device, such as a REDBACK SMS 1000, capable of terminating a DSL PPP session. At this point, the user has established a connection to the ISP using a model virtually identical to the dial-up analog model, with the notable exception of a faster connection speed and a greater available bandwidth. Importantly, the entire collection of PPP protocols is unaltered. The Ethernet is simply used as a means to carry PPP messages between a client computer and a remote server. The ISP perceives the connection as a standard PPP session from one of the ISPs subscribers. Also beneficial to the ISP is the fact that if additional user client computers initiate PPP sessions using the same DSL modem and line, no additional PVCs are required. One PVC can support an arbitrary number of PPP sessions, minimizing configuration complexity in the carrier central office.
However, DSL service using PPPoE has a number of disadvantages. First, because the user has to log-in each time a connection is desired, or each time the modem is turned on, a dynamic and not static Internet protocol (IP) address is usually assigned to the client computer and/or DSL modem. An IP address is the address of a computer attached to a TCP/IP (Transmission Control Protocol/Internet Protocol) network, where every network device (client or server) in a network must have a unique IP address. Client computers either have a static, i.e., permanent, IP address or one that is dynamically assigned to them for each communication session. The dynamic IP addresses are typically automatically assigned to the client computer by a DHCP server. Network devices that serve multiple users, such as servers and printers, require a static IP address that does not change, so that data can always be directed to that particular network device. In addition, having a static IP address allows a user to set up a Web-server on his/her client computer. Therefore, it is advantageous to have a static IP address and not a dynamic IP address as typically assigned in a PPPoE network.
Another disadvantage is that each time a PPP connection is made, the user must supply a user name, domain name, and password, such as:
Username @ domain name:user1111@company.comPassword:password1111
The need for a domain introduces additional complexity into the system, as the ISP must inform the user in advance which domain name to use.
Therefore, even with the above described advances, DSL users typically still have to at least partly configure their DSL modems themselves by manually entering configuration information into the client computer. In addition, the DSL ISPs also typically spend a substantial amount of resources providing telephone assistance to talk DSL users through the installation and configuration process. Still further, the service provider often still needs to send out technicians to the user to install and configure the DSL system. This process is both costly and time consuming.
A need therefore exists for an easier means for provisioning DSL service using PPPoE that can be undertaken by a user with little, or no, technical skill or know-how. Particularly, a system and method whereby a Broadband modem, such as a DSL modem, can be automatically self-configured would be highly desirable.